As her mother prepares to be a contestant on the 1980s television game show, "The $20,000 Pyramid," a twelve-year-old New York City girl tries to make sense of a series of mysterious notes received from an anonymous source that seems to defy the laws of time and space.

Faced with a dull summer in the city, Jane, Mark, Katharine, and Martha suddenly find themselves involved in a series of extraordinary adventures after Jane discovers an ordinary-looking coin that seems to grant wishes.

Jason and Rachel with the help of others continue the quest to triumph over Maldor.

After his parents are kidnapped, timid twelve-year-old Henry York leaves his sheltered Boston life and moves to small-town Kansas, where he and his cousin Henrietta discover and explore hidden doors in his attic room that seem to open onto other worlds.

When time goes backwards, granting six-year-old Otto his wish that his attention-stealing baby sister was never born, it keeps going backwards, and Otto finds himself getting younger and younger.

While exploring the area around his grandfather's home Gil discovers a bottle that carries messages into the past, finds a genie in a letter, and three letters that were never delivered but would have changed the course of history.

Eleven-year-old Olive finds herself drawn to the grimoire of the witches who built her house and tries to use its spells to uncover the house's magic and control the cats themselves, but the book is more wicked than it seems.

Kate, Michael, and Emma have passed from one orphanage to another in the ten years since their parents disappeared to protect them, but now they learn that they have special powers, a prophesied quest to find a magical book, and a fearsome enemy.

After returning the missing children from history to their original time periods, thirteen-year-old Jonah must save time itself when aviator Charles Lindbergh mysteriously appears and kidnaps Jonah's sister.

Connecticut middle-schooler Jake and his older sister Kady are transported by a Mayan artifact to a strange world inhabited by a mix of people from long-lost civilizations who are threatened by prehistoric creatures and an evil alchemist, the Skull King.